Polymer electrolyte fuel cells have the advantage of being operable in the ordinary temperature range and are expected to be used in a wide variety of applications. In particular, anion exchange membrane fuel cells have the following advantages: they can be produced at low cost because there is no particular need to use platinum catalysts therein; and their size can be reduced because liquid fuels can be used therein. An anion exchange membrane fuel cell includes an anode, a cathode, and a separator membrane disposed between the anode and the cathode, and an anion exchange electrolyte membrane is used as the separator membrane. Electrolyte membranes having graft chains have been known as such anion exchange electrolyte membranes (for example, Patent Literature 1).
The use of liquid fuels such as alcohols and hydrazine hydrates as fuels for anion exchange membrane fuel cells has been studied because such liquid fuels are easier to handle and more contributing to the size reduction of systems than hydrogen. In particular, the use of hydrazine hydrates as liquid fuels has been intensively studied because hydrazine hydrates have high reactivity and produce no carbon dioxide through the process of power generation. In an anion exchange membrane fuel cell using such a liquid fuel, ion conducting species are hydroxide ions, and therefore an electrolyte membrane is used in an alkaline atmosphere.